Magnetic tape recorders (longitudinal or rotary) record and playback information on and from magnetic tape transported past a stationary or rotary magnetic head(s). The magnetic tape is contained in a two reel cassette or in a single reel cartridge. A widely used single reel cartridge is the IBM 3480 cartridge which includes a single reel of magnetic tape contained in a rectangular cartridge. A leader block is connected to the free end of the tape and is accessible (1) to withdraw the leader block from the cartridge, and (2) to thread it along a tape transport path of a magnetic tape recorder to a take-up reel. It is desirable that the tape threading apparatus be reliable, cost effective and provide positive control during the entire tape threading and unthreading operation. The tape threading arrangements disclosed in the following patents have not satisfied all of these needs.
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U.S. Pat. No. 4,426,047, issued Jan. 17, 1984, inventors Richard et al.